System and method for joining dissimilar materials

ABSTRACT

An assembly includes a first structural member made from a first material, such as aluminum, a second structural member made from a second material, such as magnesium, and adapted to mate and interlock with the first member, and a third structural member made from the first material to facilitate a permanent affixation between the first and second members. The second member fits within the first member and the third member fits within the second member. The second member includes at least one aperture surrounded by a protrusion, and the third member includes at least one aperture that mates and interlocks with the protrusion. A surface of the third member is exposed through the apertures of the first and second members. The first member is welded to the third member through the apertures in order to permanently affix the first and second members to one another without metallurgical altering or local welding of the second member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Section 111(a) application relating to commonlyowned, co-pending U.S. Provisional Application Ser. No. 61/062,268entitled “SYSTEM AND METHOD FOR JOINING DISSIMILAR MATERIALS” filed Jan.24, 2008.

FIELD OF THE INVENTION

The present invention relates to a system and method for joiningstructural and mechanical parts made from dissimilar materials.

BACKGROUND OF THE INVENTION

Two main issues with joining dissimilar materials are materialcompatibility and applicability of the joining process. Moreparticularly, there are issues involved with joining aluminum tomagnesium, to steel or to composites with known joining processes, suchas fusion welding (e.g., gas metal arc welding) and solid-state welding(e.g., friction stir welding). These include metallurgicalincompatibility, which results in uncontrolled cracking in welds and/orformation of brittle intermetallics; drastic differences inelectromotive potential, which may lead to severe galvanic corrosion inthe presence of salts and/or moisture; and incompatibility in thecoefficient of thermal expansion, which could cause formation of intenseresidual stresses at joints and lead to failure under certain loadingconditions, such as stress corrosion. What is needed is an appropriatesystem and method for proper joining of structural and mechanical partsmade from dissimilar materials (e.g., metals and metal composites) toallow, among other things, the proper transmission of loads betweenthem.

SUMMARY OF THE INVENTION

A structural assembly that includes a first structural member made froma first material, a second structural member made from a second materialand adapted to mate and interlock with the first structural member, anda third structural member made from the first material to facilitate thepermanent affixation between the first and second structural members.More particularly, the first structural member includes a post made froma first material, such as aluminum, the second structural memberincludes a tube made from a second material, such as magnesium, and issized and shaped to fit within the post, and an insert made from thefirst material (e.g., aluminum) that is sized and shaped to fit withinthe tube. The post includes at least one aperture encircled by aninwardly extending protrusion, and the tube includes at least oneaperture that is sized and shaped to mate and interlock with theprotrusion when the post and tube are mated and interlocked with oneanother. When the post, tube and insert are mated and interlocked withone another, a snug fit is formed between the post and the tube andbetween the tube and the insert. In such configuration, an outer surfaceof the insert is exposed through the aperture of the post and theaperture of the tube. The aperture of the tube is substantially encasedor shielded by the protrusion of the post such that there are no exposedsurfaces of the tube in the area of the aperture of the post and theouter surface of the insert. Consequently, the aluminum post may bewelded to the aluminum insert, thereby permanently affixing, forexample, the aluminum post and the magnesium tube to one another withoutmetallurgical altering or local welding of the magnesium tube.

Further features and advantages of the invention will appear moreclearly on a reading of the detailed description of the embodiments ofthe invention, which is given below by way of example only withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the following detailed description of the embodiments considered inconjunction with the accompanying drawings, in which:

FIG. 1 is an exploded top perspective view of a post and tube jointassembly in accordance with an embodiment of the present invention;

FIG. 2A is an exploded top plan view of the post and tube joint assemblyillustrated in FIG. 1;

FIG. 2B is an exploded side elevational view of the post and tube jointassembly illustrated in FIG. 1;

FIG. 3A is a top perspective view of the post and tube joint assemblyillustrated in FIG. 1, showing an intermediate step of the componentsthereof being interlocked with one another;

FIG. 3B is a top perspective, cross-sectional view of the post and tubejoint assembly illustrated in FIG. 3A;

FIG. 3C is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 3A;

FIG. 4A is a top perspective cross-sectional view of the post and tubejoint assembly illustrated in FIG. 1, showing the components thereofinterlocked with one another;

FIG. 4B is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 4A;

FIG. 4C is an enlarged cross-sectional view showing detail 4B from FIG.4B;

FIG. 5A is a top perspective view of the post and tube joint assemblyillustrated in FIG. 4A, showing the components thereof welded to oneanother;

FIG. 5B is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 5A;

FIG. 5C is an enlarged cross-sectional view showing detail 5B from FIG.5B;

FIG. 6A is an exploded top perspective view of a post and tube jointassembly in accordance with a another embodiment of the presentinvention;

FIG. 6B is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 6A, showing an intermediate step of thecomponents thereof being interlocked with one another;

FIG. 6C is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 6A, showing the components thereofinterlocked with one another;

FIG. 6D is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 6C, showing the components thereof weldedto one another;

FIG. 7A is an exploded top perspective view of a post and tube jointassembly in accordance with yet another embodiment of the presentinvention;

FIG. 7B is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 7A, showing an intermediate step of thecomponents thereof being interlocked with one another;

FIG. 7C is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 7A, showing the components thereofinterlocked with one another;

FIG. 7D is a side cross-sectional view of the post and tube jointassembly illustrated in FIG. 7C, showing the components thereof weldedto one another;

FIG. 8A is an exploded top perspective view of a post and tube jointassembly in accordance with another embodiment of the present invention;

FIG. 8B is a cross-sectional view of an insert employed by the post andtube joint assembly illustrated in FIG. 8A;

FIG. 8C is perspective view of another embodiment of an insert employedby the post and tube joint assembly illustrated in FIG. 8A;

FIG. 8D is an exploded top perspective view of the post and tube jointassembly illustrated in FIG. 8A, showing an adhesive applied to thecomponents thereof;

FIG. 8E is a top perspective view of the post and tube joint assemblyillustrated in FIG. 8A, showing the components thereof interlocked withand welded to one another; and

FIGS. 9 through 12 show a flat sheet assembly in accordance with anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIGS. 1 through 2B, a post and tube joint assembly 10includes a hollow, rectangular-shaped post 12, a hollow,rectangular-shaped tube 14, and a hollow, rectangular-shaped insert 16.While the post 12, the tube 14 and the insert 16 are each rectangular inshape, they can consist of different shapes and sizes (e.g.,cylindrical, triangular, hexagonal, etc.) to suit the purposes of thevaried configurations to be appreciated from the teachings herein. Inaddition, the post 12 and the insert 16 may be manufactured from thesame material, while the tube 14 is manufactured from a differentmaterial. The post 12 and the insert 16, as well as the tube 14, may bemade from many types of metals suitable for the characteristicscontemplated from the teachings herein. For example, the post 12 and theinsert 16 may be made from aluminum, and, more particularly, T6 temper6061 aluminum alloy, while the tube 14 may be made from steel, analuminum alloy composite, or magnesium. The tube 14 may also be madefrom other materials, such as an organic based composite (e.g., carbonfibers bonded together) an inorganic based composite (e.g., metallicfibers braded and adhesively bonded), or similar composites.

With continued reference to FIGS. 1 through 2B, the post 12 includes afirst end 18 and a second end 20 opposite thereof, a first pair ofopposed walls 22, 24 and a second pair of opposed walls 26, 28, whichform a rectangular-shaped cavity 30. The cavity 30 is sized and shapedto slidably receive the tube 14 and the insert 16, which shall bedescribed in further detail below. The wall 22 includes a first pair ofcircular-shaped apertures 32, 34, while the wall 24 includes a secondpair of circular-shaped apertures 36, 38 (not shown in FIGS. 1 through2B, but see FIGS. 3B and 3C). Each of the apertures 32, 34 includes acircular-shaped “tea-cup” protrusion 40, 42, respectively, that extendsinto the cavity 30 from the wall 22, while each of the apertures 36, 38includes a circular-shaped “tea-cup” protrusion 44, 46, respectively,that extends into the cavity 30 from the wall 24 (not shown in FIGS. 1through 2B, but see FIGS. 3B and 3C). The aperture 32 and the aperture36 are aligned with one another, but they need not be. Similarly, theaperture 34 and the aperture 38 are aligned with one another, but theyneed not be. While the post 12 includes the apertures 32, 34 and theapertures 36, 38 (for a total of four apertures), it may include more orless than four apertures. While each of the apertures 32, 34 and theapertures 36, 38 are each circular in shape, and each of the protrusions40, 42 and the protrusions 44, 46 are circular in shape, they mayconsist of other shapes and sizes to suit the purposes of the variedconfigurations to be appreciated from the teachings herein. Theapertures 32, 34, the apertures 36, 38, the protrusions 40, 42, and theprotrusions 44, 46 may be formed from any means known in the art, suchas, for example, machining, punch forming into dies (i.e., “teacupping”), cast or forged.

Still referring to FIGS. 1 through 2B, the tube 14 includes a first end48 and a second end 50 opposite thereof, a pair of opposed walls 52, 54and a pair of opposed walls 56, 58, which form a rectangular-shapedcavity 60. The cavity 60 is sized and shaped to slidably receive theinsert 16, which shall be described in further detail below. The wall 52includes a pair of circular-shaped apertures 62, 64, while the wall 54includes a pair of circular-shaped apertures 66, 68 (not shown in FIGS.1 through 2B, but see FIGS. 3B and 3C). The aperture 62 and the aperture66 are aligned with one another, but they need not be. The aperture 64and the aperture 68 are aligned with one another, but they need not be.While the apertures 62, 64 and the apertures 66, 68 are each circular inshape, they may consist of other shapes and sizes to suit the purposesof the varied configurations to be appreciated from the teachingsherein. A slot 70 is formed within the wall 52 proximate to a corner 71where the wall 52 and the wall 56 intersect, while a slot 72 is formedwith the wall 52 proximate to a corner 73 where the wall 52 and the wall58 intersect. Similarly, a slot 74 is formed within the wall 54proximate to a corner 75 where the wall 54 and the wall 56 intersect,while a slot 76 is formed with the wall 54 proximate to a corner 77where the wall 54 and the wall 58 intersect. Each of the slots 70, 72and the slots 74, 76 have lengths that extend from the end 48 of thetube 14 to a point P1 intermediate the ends 48, 50 of the tube 14. Thelength of the slots 70, 72 and the length of the slots 74, 76 are thesame, but the lengths can be different. The functions of the slots 70,72 and the slots 74, 76 shall be described below.

Still referring to FIGS. 1 through 2B, the insert 16 includes a firstend 78 and a second end 80 opposite thereof, a first pair of opposedwalls 82, 84 and a second pair of opposed walls 86, 88, which form arectangular-shaped cavity 90. A slot 92 is formed within the wall 82proximate to a corner 93 where the wall 82 and the wall 86 intersect,while a slot 94 is formed within the wall 82 proximate to a corner 95where the wall 82 and the wall 88 intersect. Similarly, a slot 96 isformed within the wall 84 proximate to a corner 97 where the wall 84 andthe wall 86 intersect, while a slot 98 is formed within the wall 84proximate to a corner 99 where the wall 84 and the wall 88 intersect.Each of the slots 92, 94 and the slots 96, 98 has a length that extendsfrom the end 78 of the insert 16 to a point P2 intermediate the ends 78,80 of the insert 16. The length of the slots 92, 94 and the length ofthe slots 96, 98 are the same, but the lengths can be different. Theinsert 16 includes a first retainment tab 100 that extends outwardlyfrom the wall 82 at the end 78 of the insert 16, while a secondretainment tab 102 extends outwardly from the wall 84 at the end 78 ofthe insert 16. Each of the tabs 100, 102 has a length that issubstantially the width of the walls 82, 84, respectively. The tab 100includes a curved outer surface 101, while the tab 102 includes a curvedouter surface 103 (see FIG. 2B). The functions of the slots, 92, 94, theslots 96, 98, and the retainment tabs 100, 102 shall be described below.

FIGS. 3A through 3C show an intermediate step of assembling the post 12,the tube 14 and the insert 16 with one another. More particularly, theend 80 of the insert 16 is inserted into the cavity 60 of the tube 14 atthe end 48 thereof. In such position, the retainment tabs 100, 102 ofthe insert 16 abut against the end 48 of the tube 14, which inhibit theinsert 16 from sliding out the end 50 of the tube 14 during assembly.The cavity 60 of the tube 14 is sized and shaped to accommodate thereceipt of the insert 16 and firmly retain the insert 16 therein.

Next, the tube 14 and the insert 16 assembly as described above areslidably inserted into the cavity 30 of the post 12 at an end 20thereof. The cavity 30 of the post 12 is sized and shaped such that thetube 14 and the insert 16 elastically deflect inwardly when the tube 14and the insert 16 are inserted into the post 12 (see FIGS. 3B and 3C).More particularly, as the tube 14 and the insert 16 assembly areinserted into the post 12, the tab 100 of the insert 16 reaches theprotrusion 42 of the post 12 and the tab 102 reaches the protrusion 46of the post 12. At this point, the curved surfaces 101, 103 of the tabs100, 102 and the “tea-cup” shapes of the protrusions 42, 46 enable thetabs 100, 102 to travel over (i.e., ramp over) the protrusions 42, 46,respectively. As the tabs 100, 102 travel over the protrusions 42, 46,resulting forces act against the tabs 100, 102 and, in turn, against thefirst end 48 of the tube 14. As a result of such forces, the walls 52,54 of the tube 14 deflect inwardly, while the walls 82, 84 of the insert16 deflect inwardly. The slots 70, 72 of the tube 14 facilitate thedeflection of the wall 52 of the tube 14 inwardly, while the slots 74,76 of the tube 14 facilitate the deflection of the wall 54 of the tube14 inwardly. Similarly, the slots 92, 94 of the insert 16 facilitate thedeflection of the wall 82 of the insert 16 inwardly, while the slots 96,98 of the insert 16 facilitate the deflection of the wall 84 of theinsert 16 inwardly. As indicated above, the lengths of the slots 70, 72and the slots 74, 76 of the tube 14 are equal in order to facilitateuniform deflection of the walls 52, 54 of the tube 14. Similarly, thelengths of the slots 92, 94 and the slots 96, 98 of the insert 16 areequal in order to facilitate uniform deflection of the walls 82, 84 ofthe insert. However, the aforesaid lengths can be adjusted (e.g.,shortened or lengthened) to suit the purposes of the variedconfigurations to be appreciated from the teachings herein.

It is also noted that the apertures 32, 34 of the post 12 are notaligned with one another along axis A-A, as shown in FIGS. 2A and 3A,and that the apertures 36, 38 of the post 12 are not aligned with oneanother along axis A-A. This configuration prevents the aperture 62 frommating with the protrusion 40 and the aperture 66 from mating with theprotrusion 44. As a result, the tube 14 and the insert 16 assembly areprevented from interlocking with the post 12 prematurely.

As the tube 14 and the insert 16 assembly continues to be insertedwithin the post 12, the protrusions 42, 46 act against the wall 52 ofthe tube 14 to maintain the deflection of the tube 14 and the insert 16as discussed above. Once again, the curved surfaces 101, 103 of the tabs100, 102 and the “tea-cup” shapes of the protrusions 42, 46 enable thetabs 100, 102 to slide over the protrusions 44, 48, respectively.

FIGS. 4A through 4C show the tube 14 and the insert 16 assembly fullyinserted within the post 12 and snapped into place. More particularly,the apertures 62, 64 of the tube 14 engage and cooperate with theprotrusions 40, 42 of the post 12, respectively, while the apertures 66,68 of the tube 14 engage and cooperate with the protrusions 44, 46 ofthe post, respectively. In such manner, the walls 52, 54 of the tube 14and the walls 82, 84 of the insert 16 spring back into theirsubstantially same original position (i.e., before deflection) and arelocked into place within the post 12. As a result, the protrusions 40,42, are aligned and interlocked with the apertures 62, 64, respectively,while the protrusions 44, 46 are aligned and interlocked with theapertures 66, 68, respectively. The thickness of the walls 52, 54 of thetube 14 is sized appropriately to enable the protrusions 40, 42, 44, 46to sufficiently mate and interlock with the respective apertures 62, 64,66, 68. It is also noted that the tube 14 and the insert 16 are designedand manufactured such that their elastic deformation is within the rangeof approximately 99-100% (e.g., no plastic deformation at >0.2 yieldstrengths); and, therefore, such components can carry out the mechanicalinterlocking process described herein.

FIGS. 5A through 5C show the welding of the post 12 to the insert 16,which are made from the same material (e.g., aluminum). Moreparticularly, welds 104 are placed within each of the apertures 32, 34of the post 12 and the apertures 62, 64 of the tube 14, resulting inwelded joints between the protrusions 40, 42 and the wall 82 of theinsert 16. Similarly, welds 106 are placed within the apertures 36, 38of the post 12 and the apertures 66, 68 of the tube 14, resulting inwelded joints between the protrusions 44, 46 and the wall 84 the insert16. Since the post 12 and the insert 16, which are made from the samematerial (e.g., aluminum), are permanently welded to one another by thewelds 104, 106, the tube 14, which is made from a different material(e.g., magnesium) is permanently retained within the post 12.Consequently, the mechanical interlock between the post 12 and the tube14 described above is permanently affixed.

The welds 102, 104 may be made from any welding process known in theart, such as fusion-based (e.g., GMAW, GTAW, LBW, LSBW, etc.) orsolid-state based (e.g., FSW, FW Plunge, etc.). Alternatively, the welds102, 104 need not be included, and the welding process described abovecould be substituted with any other joining and fixation processes knownin the art, such as rivets, bolts, screws, etc. that enable the post 12and tube 14 to be secured together in a manner that ensures themechanical interlocks between them do not separate.

The mechanical interlocking features of the post and joint assembly 10enable load transmission through the post 12 and the tube 14, whilesimultaneously keeping the subsequent joining operations localized andconfined to joining the post 12 and the insert 16 (which are made of thesame material) and separate from the tube 14.

Another embodiment of the present invention is illustrated in FIGS. 6Athrough 6D. The embodiment shown in FIGS. 6A through 6D includes thesame features and is assembled in the same manner as the embodimentshown in FIGS. 1 through 5C, with the exception that the post 12 has twopairs of circular-shaped apertures 32, 34 on the wall 22 thereof and twopairs of circular-shaped apertures 36, 38 on the wall 24 thereof, whilethe tube 14 has two pairs of circular-shaped apertures 62, 64 on thewall 52 thereof and two pairs of circular-shaped apertures 66, 68 on thewall 54 thereof. In the same manner as the embodiment shown in FIGS. 1through 5C, the insert 16 is slidably inserted into the tube 14, and thetube 14 and the insert 16 assembly is slidably inserted into the post 16and locked into place (see FIGS. 6B and 6C). Afterwards, the mechanicalinterlock between the post 12 and the tube 14 are permanently affixed bywelding the post 12 to the insert 16 by welds 104 through each of theapertures 32, 34 of the post 12 and the apertures 62, 64 of the tube 14and welds 106 through each of the apertures 36, 38 of the post 12 andthe apertures 62, 64 of the tube 14.

Another embodiment of the present invention is illustrated in FIGS. 7Athrough 7D. The embodiment shown in FIGS. 7A through 7D includes thesame features and is assembled in the same manner as the embodimentshown in FIGS. 1 through 5C, with the exception that the post 12 has twopairs of oblong-shaped slots 32, 34 on the wall 22 thereof and two pairsof oblong-shaped slots 36, 38 on the wall 24 thereof, while the tube 14has two pairs of oblong-shaped slots 62, 64 on the wall 52 thereof andtwo pairs of oblong-shaped slots 66, 68 on the wall 54 thereof. In thesame manner as the embodiment shown in FIGS. 1 through 5C, the insert 16is slidably inserted into the tube 14, and the tube 14 and the insert 16assembly is slidably inserted into the post 16 and locked into place(see FIGS. 7B and 7C). Afterwards, the mechanical interlock between thepost 12 and the tube 14 are permanently affixed by welding the post 12to the insert 16 by welds 104 through each of the slots 32, 34 of thepost 12 and the slots 62, 64 of the tube 14 and by welds 106 througheach of the slots 36, 38 of the post 12 and the slots 66, 68 of the tube14.

Another embodiment of the present invention is illustrated in FIGS. 8Athrough 8D. Elements illustrated in FIGS. 8A through 8D that correspondto the elements described above with reference to FIGS. 1 though 5C havebeen designated by corresponding reference numerals increased by twohundred (200). The embodiment of FIGS. 8A through 8D operates in thesame manner as the embodiment of FIGS. 1 through 5C, unless it isotherwise stated.

FIGS. 8A through 8D show a post and tube joint assembly 210 thatincludes a hollow, rectangular-shaped post 212, a hollow,rectangular-shaped tube 214, and a hollow, rectangular-shaped insert216. These components include the same features as those correspondingto the embodiment shown in FIGS. 1 though 5C described above, with theexception that the tube 214 includes rectangular-shaped channels 201formed within and extending transversely across an outer surface of awall 252 and an outer surface of a wall 254 (not shown in the Figures),and T-shaped channels 203 formed within an outer surface of a wall 258and an outer surface of a wall 256 (not shown in the Figures). Inaddition, the insert 216 includes oblong-shaped channels 205 formedwithin an outer surface of a wall 288 and an outer surface of a wall 286(not shown in the Figures). FIGS. 8B and 8C show additional embodimentsof the insert 216, which include channels 207 and 209, respectively,that consist of different shapes and sizes. Accordingly, the channels201, 203, 205 can consist of a variety shapes and sizes and in anynumber other than those shown in the Figures. Each of the channels 201,203 of the tube 214 and the channels 205 of the insert 214 are adaptedto receive a sealant and/or an adhesive 211, which provides additionalbonding when the post 212, the tube 214 and the insert 216 areinterlocked with and welded to one another (see FIG. 8D). In addition,when the post 212 and the tube 214 are interlocked, a sealant and/oradhesive 211 may be applied between the post 212 and the tube 214 aroundthe perimeter of an end 220 of the post 212, as shown in FIG. 8E. Thesealant/adhesive 211 is used to improve the overall performance andstrength (e.g., mechanical strength, corrosion resistance, etc.) of theassembly 210, as well as to seal area A between the post 212 and thetube 214 to prevent the intrusion of foreign elements (see FIG. 8E). Theadhesive/sealant 211 may be applied by injection or manually brushed on.Alternatively, the use of heat-activated or non-heat activated adhesivesand/or sealing tapes can be utilized. The adhesive or sealant 211 may beapplied prior to or after the mechanical interlocking of the assembly210, as appropriate.

FIGS. 9 through 14 show a similar system and method with respect to aflat sheet assembly 310. More particularly, FIG. 9 shows the assembly310 prior to lock-joining the components thereof, which include a firstrectangular-shaped sheet 312, a second rectangular-shaped sheet 314, anda third rectangular-shaped sheet 316 that is sandwiched between thefirst and second sheets 312, 314. While the sheets 312, 314, 316 areeach rectangular in shape, they can consist of different shapes andsizes (e.g., square, triangular, circular, oblong, etc.) to suit thepurposes of the varied configurations to be appreciated from theteachings herein. In addition, the sheets 312, 314 are each manufacturedfrom the same material, such as aluminum, while the sheet 316 ismanufactured from a different material, such as magnesium.Alternatively, the sheets 312, 314, as well as the sheet 316, may bemade from other types of metals suitable for the characteristicscontemplated from the teachings herein. For example, the sheets 312, 314may be made from aluminum, while the sheet 316 may be made from steel oran aluminum based composite. The sheet 316 may also be made from othermaterials, such as an organic based composite (e.g., carbon fibersbonded together) an inorganic based composite (e.g., metallic fibersbraded and adhesively bonded), or similar composites.

Referring to FIGS. 9 and 10, the sheet 312 includes a pair ofcircular-shaped apertures 318, 320 encircled by “tea-cup” shapedprotrusions 322, 324 that outwardly extend from a surface 326 of thesheet 312. Referring only to FIG. 9, the sheet 316 includes twocircular-shaped apertures 328, 330 that are sized and shaped to receivethe protrusions 322, 324 of the sheet 312. As shown in FIG. 11, anadhesive 332 may be applied to a surface 334 of the sheet 312 and asurface 336 of the sheet 314. FIG. 12 shows the assembly of the sheets312, 314, 316, whereby the protrusions 322, 324 of the sheet 312 arereceived by the apertures 328, 330 of the sheet 316. In FIG. 13, thesheets 312, 314, 316 are clamped together for preparation of a weldingprocess and facilitating the adhesion between them. FIG. 14 shows thedeposition of a GMA spot weld 338 between the sheets 312, 314 which aremade from the same material (e.g., aluminum) with the sheet 316 (whichis made from magnesium) interlocked between them. As a result the sheet316 is interlocked with the between the aluminum sheets 312, 314.

The method includes lock-joining together parts made from dissimilarmaterials through the use of interlocking means on the parts at thejoints betwee n them, and the use of another (i.e., secondary) joiningprocess whose application is separate from and confined to joining twoparts made from the same material, which ensures that the mechanicalinterlocks between the parts of dissimilar materials do not becomeseparated.

The term “snug fit” is defined as a gap or space (or a lack thereofbetween each of the protrusions 40, 42, 44, 46 of the post 12 and theouter surface of the insert 16 being in the range of zero up to adimension that does not expose a surface of the tube 14 to the weldingprocess. The term “mate” is defined as to join, fit, associate, assembleor couple parts or components with one another. The term “interlock”means to lock, fasten or fix parts or components with one another toensure a stable and desirable coordinately functioning structure oraction.

It should be understood that the embodiments described herein are merelyexemplary and that a person skilled in the art may make many variationsand modifications without departing from the spirit and scope of theinvention. Accordingly, all such variations and modifications areintended to be included within the scope of the embodiments describedherein as defined in the appended claims.

1. An assembly, comprising: a first structural member made from a firstmaterial and having at least one locking member; a second structuralmember made from a second material and having at least one retentionstructure, the at least one locking member of the first structuralmember is sized and shaped to mate with the at least one retentionstructure of the second structural member so as to interlock the firstand second structural members with one another; a third structuralmember made from the first material and mated with the first and secondstructural members, the first structural member and the third structuralmember being joined directly to one another so as to facilitate apermanent connection between the first and second structural members. 2.The assembly of claim 1, wherein the first structural member includes afirst surface and a second surface opposite the first surface, andwherein the at least one locking member of the first structural memberincludes at least one protrusion extending from the second surface, andwherein the second structural member includes a first surface and asecond surface opposite the first surface of the second structuralmember, the at least one retention structure of the second structuralmember includes an aperture extending from the first surface of thesecond structural member to the second surface of the second structuralmember.
 3. The assembly of claim 2, wherein the first structural memberincludes at least one aperture that extends from the first surface ofthe first structural member to the second surface of the firststructural member, the at least one protrusion surrounds the at leastone aperture of the first structural member, the at least one apertureof the first structural member and the at least one aperture of thesecond structural member being aligned substantially with one another.4. The assembly of claim 3, wherein the third structural member includesa first surface, the first, second and third structural members beingpositioned relative to one another such that the first surface of thethird structural member is exposed through the at least one aperture ofthe first structural member and the at least one aperture of the secondstructural member.
 5. The assembly of claim 4, wherein the at least oneprotrusion of the first structural member includes a plurality ofprotrusions, and the at least one aperture of the second structuralmember includes a plurality of apertures, one of the plurality ofprotrusions of the first structural member being sized and shaped tomate with a corresponding one of the plurality of apertures of thesecond structural member.
 6. The assembly of claim 5, wherein the atleast one aperture of the first structural member includes a pluralityof apertures, one of the plurality of protrusions of the firststructural member surrounds a corresponding one of the plurality ofapertures of the first structural member, and one of the plurality ofapertures of the first structural member and a corresponding one of theplurality of apertures of the second structural member being alignedsubstantially with one another.
 7. The assembly of claim 6, wherein eachof the plurality of protrusions of the first structural member is weldedto the first surface of the third structural member.
 8. The assembly ofclaim 7, wherein each of the plurality of apertures of the firststructural member is circular in shape, and each of the plurality ofapertures of the second structural members is circular in shape.
 9. Theassembly of claim 7, wherein the first material is aluminum.
 10. Theassembly of claim 8, wherein the second material is magnesium.
 11. Theassembly of claim 8, wherein the second material is steel.
 12. Theassembly of claim 8, wherein the second material is an organic basedcomposite.
 13. The assembly of claim 8, wherein the second material isan inorganic based composite.
 14. An assembly, comprising: a firststructural member made from a first material and having a first end, asecond end opposite the first end, and a cavity extending from the firstend to the second end; a second structural member made from a secondmaterial and having a first end, a second end opposite the first end ofthe second structural member, and a cavity extending from the first endof the second structural member to the second end of the secondstructural member; and a third structural member made from the firstmaterial and having a first end and a second end opposite thereof, thecavity of the second structural member is sized and shaped to receiveslidably the third structural member at the first end of the secondstructural member, the cavity of the first structural member is sizedand shaped to receive slidably the second and third structural membersat the second end of the first structural member, the first structuralmember and the third structural member being joined directly to oneanother so as to facilitate a permanent connection between the first andsecond structural members.
 15. The assembly of claim 14, wherein thefirst structural member includes a first wall having a first surface, asecond surface opposite the first surface, and at least one protrusionextending from the second surface, the second structural member includesa first wall having a first surface, a second surface opposite the firstsurface of the first wall of the second structural member, and at leastone aperture extending from the first surface of the first wall of thesecond structural member to the second surface of the first wall of thesecond structural member, the at least one protrusion is sized andshaped to mate with the at least one aperture so as to interlock thefirst and second structural members with one another.
 16. The assemblyof claim 15, wherein the first structural member includes at least oneaperture that extends from the first surface of the first wall of thefirst structural member to the second surface of the first wall of thefirst structural member, the at least one protrusion surrounds the atleast one aperture of the first structural member, and the at least oneaperture of the first structural member and the at least one aperture ofthe second structural member being aligned substantially with oneanother.
 17. The assembly of claim 16, wherein the third structuralmember includes a first wall having a first surface and a second surfaceopposite the first surface of the third structural member, the first,second and third structural members being positioned relative to oneanother such that the first surface of the first wall of the thirdstructural member is exposed through the at least one aperture of thefirst structural member and the at least one aperture of the secondstructural member.
 18. The assembly of claim 17, wherein the at leastone protrusion of the first structural member is welded to the firstsurface of the first wall of the third structural member.
 19. Theassembly of claim 18, wherein the at least one protrusion of the firststructural member includes a plurality of protrusions, and the at leastone aperture of the second structural member includes a plurality ofapertures, one of the plurality of protrusions of the first structuralmember being sized and shaped to mate with a corresponding one of theplurality of apertures of the second structural member.
 20. The assemblyof claim 19, wherein the at least one aperture of the first structuralmember includes a plurality of apertures, one of the plurality ofprotrusions of the first structural member surrounds a corresponding oneof the plurality of apertures of the first structural member, and one ofthe plurality of apertures of the first structural member and acorresponding one of the plurality of apertures of the second structuralmember being aligned substantially with one another.
 21. The assembly ofclaim 20, wherein the first structural member includes a second wallhaving a first surface, a second surface opposite the first surface ofthe second wall, and at least one protrusion extending from the secondsurface of the second wall, the second structural member includes asecond wall having a first surface, a second surface opposite the firstsurface of the second wall of the second structural member, and at leastone aperture extending from the first surface of the second wall of thesecond structural member to the second surface of the second wall of thesecond structural member, the at least one protrusion of the second wallof the first structural member is sized and shaped to mate with the atleast one aperture of the second wall of the second structural member soas to interlock the first and second structural members with oneanother.
 22. The assembly of claim 21, wherein the first structuralmember includes at least one aperture that extends from the firstsurface of the second wall of the first structural member to the secondsurface of the second wall of the first structural member, the at leastone protrusion of the second wall of the first structural membersurrounds the at least one aperture of the second wall of the firststructural member, and the at least one aperture of the second wall ofthe first structural member and the at least one aperture of the secondwall of the second structural member being aligned substantially withone another.
 23. The assembly of claim 22, wherein the third structuralmember includes a second wall having a first surface and a secondsurface opposite the first surface of the second wall of the thirdstructural member, the first, second and third structural members beingpositioned relative to one another such that the first surface of thesecond wall of the third structural member is exposed through the atleast one aperture of the second wall of the first structural member andthe at least one aperture of the second wall of the second structuralmember.
 24. The assembly of claim 23, wherein the at least oneprotrusion of the first structural member is welded to the first surfaceof the second wall of the third structural member.
 25. The assembly ofclaim 24, wherein the at least one protrusion of the second wall of thefirst structural member includes a plurality of protrusions, and the atleast one aperture of the second wall of the second structural memberincludes a plurality of apertures, one of the plurality of protrusionsof the second wall of the first structural member being sized and shapedto mate with a corresponding one of the plurality of apertures of thesecond wall of the second structural member.
 26. The assembly of claim25, wherein the at least one aperture of the second wall of the firststructural member includes a plurality of apertures, one of theplurality of protrusions of the second wall of the first structuralmember surrounds a corresponding one of the plurality of apertures ofthe second wall of the first structural member, and one of the pluralityof apertures of the second wall of the first structural member and acorresponding one of the plurality of apertures of the second wall ofthe second structural member being aligned substantially with oneanother.
 27. The assembly of claim 26, wherein the third structuralmember includes a cavity extending from the first end of the thirdstructural member to the second end of the third structural member, andwherein the second structural member includes a pair of slots formedwithin the first wall of the second structural member and each extendingfrom the first end of the second structural member to a point distalfrom the first end of the second structural member, and the thirdstructural member includes a pair of slots formed within the first wallof the third structural member and each extending from the first end ofthe third structural member to a point distal from the first end of thethird structural member, each of the pair of slots of the secondstructural member being sized and shaped to enable the first wall of thesecond structural member to move between an undeflected position to adeflected position, the first wall of the second structural member isurged from the undeflected position toward the deflected position whenthe second structural member is partially inserted within the cavity ofthe first structural member, and the first wall of the second structuralmember returns from the deflected position to substantially its theundeflected position when the second structural member is fully insertedwithin the cavity of the first structural member, and each of the pairof slots of the third structural member being sized and shaped to enablethe first wall of the third structural member to move between anundeflected position to a deflected position, the first wall of thethird structural member is urged from its the undeflected positiontoward its the deflected position when the second structural member ispartially inserted within the cavity of the first structural member, andthe first wall of the third structural member returns from its thedeflected position to substantially its the undeflected position whenthe second structural member is fully inserted within the cavity of thefirst structural member.
 28. The assembly of claim 27, wherein thesecond structural member includes a second pair of slots formed withinthe second wall of the second structural member and each extending fromthe first end of the second structural member to a point distal from thefirst end of the second structural member, and the third structuralmember includes a second pair of slots formed within the second wall ofthe third structural member and each extending from the first end of thethird structural member to a point distal from the first end of thethird structural member, each of the second pair of slots of the secondstructural member being sized and shaped to enable the second wall ofthe second structural member to move between an undeflected position toa deflected position, the second wall of the second structural member isurged from its the undeflected position toward its the deflectedposition when the second structural member is partially inserted withinthe cavity of the first structural member, and the second wall of thesecond structural member returns from its the deflected position tosubstantially its the undeflected position when the second structuralmember is fully inserted within the cavity of the first structuralmember, and each of the second pair of slots of the third structuralmember being sized and shaped to enable the second wall of the thirdstructural member to move between an undeflected position to a deflectedposition, the second wall of the third structural member is urged fromits the undeflected position toward its the deflected position when thesecond structural member is partially inserted within the cavity of thefirst structural member, and the second wall of the third structuralmember returns from its the deflected position to substantially its theundeflected position when the second structural member is fully insertedwithin the cavity of the first structural member.
 29. The assembly ofclaim 28, wherein each of the first, second and third structural membersis generally rectangular in cross section.
 30. The assembly of claim 28,wherein the first material is aluminum.
 31. The assembly of claim 30,wherein the second material is magnesium.
 32. The assembly of claim 30,wherein the second material is steel.
 33. The assembly of claim 30,wherein the second material is an organic based composite.
 34. Theassembly of claim 30, wherein the second material is an inorganic basedcomposite.
 35. A method, comprising the steps of: providing a firststructural member made from a first material and having at least onelocking member; connecting a second structural member, made from asecond material and having at least one retention structure, to thefirst structural member, the at least one locking member of the firststructural member is sized and shaped to mate with the at least oneretention structure of the second structural member so as to interlockthe first and second structural members when the are connected to oneanother; providing a third structural member, made from the firstmaterial, and mating it with the first and second structural members;and joining directly the first structural member and the thirdstructural member with one another so as to facilitate a permanentconnection between the first and second structural members.